This invention relates to a packaging unit which prevents or restricts access to the contents. Such packaging units are widely used for medicinal preparations, paints, varnishes, cleansing agents, rust removal agents and the like. These units generally include a container having a closure or plug which is designed to be difficult to open or remove. The closure or plug is often termed "safety closures" or "safety plugs", and inasmuch as primarily children make up the group of people to whom unwarranted opening is to be denied, they are often called "childproof closures".
A known design for a safety closure consists essentially of an internal cylinder provided with a sealing lip or bead and a flange-like continuation of the cylinder which mounts on the edge of the container opening. If desired, a retaining means for the contents may be provided which projects into the interior of the container.
An object of the invention is to provide a packaging unit with a safety closure which is simple and cheap to produce and which can be filled and sealed on standard automated packing lines such as are in existence in industry, and in the pharmaceutical industry in particular, without the need for significant modification.
This object is attained by the present invention in which a flange-like part of the safety closure projecting above the edge of the container opening has a maximum external diameter equal to the external diameter of the opening and tapers from the edge of the opening to the center so that no grippable peripheral area is provided and in which a slide is mounted in a flange-like part of the closure to move radially to provide a surface which may be used to remove the closure from the opening.
The invention is described in greater detail by means of example embodiments and reference to the drawings.